S3279 Diagnostic Yield of Duodenal Aspirates/Culture for SIBO or SIFO Among Patients With Cystic Fibrosis

Abstract

Introduction: Cystic fibrosis (CF) is a debilitating autosomal recessive multisystem disorder involving the gastrointestinal (GI) tract. CF patients are predisposed to developing small intestinal bacterial overgrowth (SIBO) or fungal overgrowth (SIFO) secondary to altered gut motility and mucus accumulation in the small intestine. To date, there has been little systemic study of SIBO/SIFO among cystic fibrosis patients using the gold standard test of duodenal aspirates/culture for its diagnosis. We aimed to determine the diagnostic yield of duodenal aspirates in the diagnosis of SIBO/SIFO among CF patients with GI symptoms. Methods: This was a retrospective analysis of CF patients referred to our tertiary care enter with unexplained GI symptoms of more than 1 year from January 2017 to May 2021 and suspected to have SIBO/SIFO. These patients underwent endoscopy with duodenal aspirates (aerobic, anaerobic and fungal cultures) using a 3mm Liguory catheter under aseptic conditions using the Rao technique (Videogie;https://doi.org/10.1016/j.vgie.2020.11.008). A colony count of >103 CFU/mL was determined to be diagnostic for SIBO or SIFO. Results: Twelve patients (male/female = 6/6) were included in this study and 6 of whom (50%) tested positive for either SIBO or SIFO on the duodenal aspirates. Three patients (50%) had both SIBO and SIFO, 1 (17%) had SIBO only and 2 (33%) had SIFO only. Streptococcus, Rothia, Klebsiella, Methicillin-Resistant Staphylococcus Aureus, Escherichia coli, Lactobacillus, multiple anaerobes, Candida albicans and Cryptococcus not neoformans were cultured (Table). There were no significant differences in the comorbidities (diabetes, gastroparesis, constipation) and proton pump inhibitor use among CF patients with positive and negative duodenal aspirates. Conclusion: In this pilot study, we found a higher diagnostic yield for identifying SIBO/SIFO among CF patients with GI symptoms utilizing duodenal aspirates/culture. The diagnostic yield of 50% is higher than the yield of glucose breath testing for diagnosing SIBO in the literature that ranges from 31-37%. Given the risk of multidrug resistant organisms among CF patients owing to the use of multiple antibiotics for recurring pulmonary infections, the use of duodenal aspirates/culture and sensitivity could not only provide an accurate diagnosis of SIBO/SIFO but also facilitate the tailoring of treatment regimens based on antibiotic and antifungal susceptibility.Table 1.: Demographic Characteristics of the Study Population and Microbial Culture Results of the Duodenal Aspirates Abbreviations: SIBO- small intestinal bacterial overgrowth, SIFO- small intestinal fungal overgrowth, BMI- body mass index, MRSA- Methicillin-resistant Staphylococcus aureus.